Transform.TransformDirection
TransformDirection(direction: Vector3): Vector3;
Description

Transforms direction from local space to world space.

This operation is not affected by scale or position of the transform. The returned vector has the same length as direction.
	// Calculate the x-axis relative to the camera
	var cam : Transform = Camera.main.transform;
	var cameraRelativeRight : Vector3 = cam.TransformDirection (Vector3.right);
	// Apply a force relative to the camera's x-axis
	rigidbody.AddForce (cameraRelativeRight * 10);
TransformDirection(x: float, y: float, z: float): Vector3;
Description

Transforms direction x, y, z from local space to world space.

This operation is not affected by scale or position of the transform. The returned vector has the same length as direction.
	// Calculate the x-axis relative to the camera
	var cam : Transform = Camera.main.transform;
	var cameraRelativeRight : Vector3 = cam.TransformDirection (1, 0, 0);
	// Apply a force relative to the camera's x-axis
	rigidbody.AddForce (cameraRelativeRight * 10);